The objective of this work is to examine the feasibility of electrically conductive hydrogel composites as scaffolds in tissue engineering and tissue regeneration, and to understand the properties of the composites as a growth matrix for clinically relevant cell lines. The composite is comprised of carbon nanobrushes embedded in a biocompatible poloxamer gel. This work assesses the ability of such composite gels to support the growth of fibroblasts and myocytes and eventually serve as a matrix to stimulate wound closure. In such a model, fibroblasts and myocytes are seeded on the hydrogel and bathed in culture medium. The experimental model assesses the ability of fibroblasts and myocytes to grow into and adhere to the gel. The work demonstrates that carbon nanobrushes can be dispersed within poloxamer gels, and that fibroblasts and myocytes can proliferate within homogenously dispersed carbon nanobrush-containing poloxamer gels. This work also examines the effects of carbon nanobrush content on the rheological properties of the poloxamer gel matrix and shows an improvement in several areas in the presence of carbon nanobrushes. Future work will examine the effects of design parameters such as carbon nanobrush content and matrix structure on wound healing, as well as the growth of tendons and other cell lines within the hydrogel composites. This work has relevance for tissue and cellular engineering and tissue regeneration in clinical medicine.

Growth trajectories are a biological process important to plant and animal breeding, and to evolutionary genetic studies. In this article, we report the detection of quantitative trait loci (QTLs) responsible for growth trajectories in poplars that are used as a model system for the study of forest biology. These QTLs were localized on a genetic linkage map of polymorphic markers using a statistical mapping method incorporating growth-curve models. The effects of the QTLs on growth are described as a function of age, so that age-specific changes in QTL effects can be readily projected throughout the entire growth process. The QTLs identified display increased effects on growth when trees age, yet the timing of QTL activation is earlier for stem height than diameter, which is consistent with the ecological viewpoint of canopy competition. The implications of the results for breeding and silviculture are discussed.

A given number of bullets will be fired sequentially in an attempt to destroy as many targets as possible from a fixed number of targets. The probability of destroying a target at each shot is known. After each shot, there is a report on the state for the target; destroyed or intact. The reports are subject to the usual two types of errors and the probabilities of making these errors are also known. This paper shows that the myopic decision strategy that picks the next target to be the one with the highest intact posterior probability is the optimal strategy.

An oxygen treatment in a high density plasma system is used to effectively remove the fluorocarbon polymer that deposits on the silicon substrate surface after an oxide etch process. Schottky current-voltage analysis, spectroscopic ellipsometry, and X-ray photoelectron spectroscopy, are used to investigate the effectiveness of the in-situ O2 clean process. Polymeric material deposited in the high density plasma system is shown to be completely removed with no polymeric residue remaining on the wafer surface after cleaning. Deep contacts, greater than 2 um, are shown to have the polymer effectively removed with the in-situ O2 clean process. Minimal oxide growth during the plasma clean is observed. Also, there is no etching of the silicon substrate with the O2 clean process. A comparison is made to an ozone clean process that is known to effectively clean organic contaminants from silicon surfaces.

An oxygen treatment in a high density plasma system is used to effectively remove the fluorocarbon polymer that deposits on the silicon substrate surface after an oxide etch process. Schottky current-voltage analysis, spectroscopic ellipsometry, and X-ray photoelectron spectroscopy, are used to investigate the effectiveness of the in-situ O2 clean process. Polymeric material deposited in the high density plasma system is shown to be completely removed with no polymeric residue remaining on the wafer surface after cleaning. Deep contacts, greater than 2 um, are shown to have the polymer effectively removed with the in-situ O2 clean process. Minimal oxide growth during the plasma clean is observed. Also, there is no etching of the silicon substrate with the O2 clean process. A comparison is made to an ozone clean process that is known to effectively clean organic contaminants from silicon surfaces.

Processable polymeric nonlinear optical materials can be synthesized by functionalizing a glassy macromolecule with chromophores having large quadratic hyperpolarizabilities, followed by poling in an electric field. In the present case, the functionalization of polystyrene with 4- (4-nitrophenylaza)(N-ethyl)(2-hydroxyethyl))aniline, 4-(4-N,N-dimethylaminostyryl) pyridine, and N-(4-nitrophenyl)-L-prolinol is described. Particularly noteworthy is the high level of chromophore units that can be incorporated into transparent films of these materials, the high second harmonic coefficients that can be achieved (as high as d33 – 11 × 10-9 esu at 1064 nm), and the long-term temporal stability of the second harmonic generation capacity.

Optimal stopping rules under various conditions are obtained for a proofreader who has a probability p (known or unknown) of detecting a misprint in proofsheets which contain an unknown but Poisson-distributed number of misprints.

It is shown in this note that if the population increases geometrically, then the asymptotic distribution for the inter-record times is also geometric. The records in Olympic games are used as an example. Also, it is noted that the rapid breaking of Olympic records is not due mainly to the increase in population.

The classical secretary problem is generalized to admit stochastically successful procurement of previous interviewees, but each has a certain probability of refusing the offer. A general formula for solving this problem is obtained. Two special cases: constant probability of refusing and geometric probability of refusing are discussed in detail. The optimal stopping rules in these two cases turn out to be simple.